JPS62115148A - Radiographic information reader - Google Patents

Abstract

PURPOSE:To prevent noise from penetrating a read signal due to an erasing light by arranging fixedly the second erasing part on a reader body independently of an erasing part on a moving dus substrate and performing the erasing operation by the erasing part at all times except the photographing time and the read operation time. CONSTITUTION:The radiation passing an object M is received by a stimulable luminescent phosphor plate 2 of a radiographic information reader 1 to record the image of the object M as a latent image. This phosphor plate 2 is moved vertically in the reader 1 by an elevating mechanism. A start and read unit 3 is arranged on the rear face of the phosphor plate 2, and the first erasing lamp 14 is provided in a reflecting hood 15 having the light emitting face above the light condensing end of a light condensing body 12 of the unit 3. Plural reflecting hoods 181-18n are fixed to the rear inside face of the reader 1, and the second erasing lamps 171-17n are arranged on hoods 181-18n. Erasing is performed by the lamp 14 in accordance with movement of the unit 3, and erasing is performed by lamps 171-17n at all times except the photographing time and the read operation time to prevent penetration of the noise.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a reading device for radiation image information stored and recorded on a stimulable phosphor plate.

-Background of the Invention- When a stimulable phosphor is irradiated with radiation such as X-rays or ultraviolet rays, it can accumulate part of the energy of this radiation, and when it is irradiated with excitation light, it can accumulate some of the energy of this radiation. It emits stimulated light with an intensity that corresponds to the energy. Utilizing this property, radiation image information of the subject is recorded and accumulated as a latent image by irradiating the stimulable phosphor plate with radiation that has passed through the subject, and this stimulable phosphor plate is then exposed to a laser beam. A radiation image is created by irradiating excitation light such as light and detecting the amount of stimulated luminescence corresponding to the density of the latent image (the amount of energy accumulated in each part of the phosphor) with a photodetector, and further processing the detection signal. Devices that read image information and record the read image information on photographic film or display it on a display device are attracting attention.

In such devices, the afterimage after reading can be erased by irradiating the stimulable phosphor plate with a large amount of light, and by providing this erasing means, the stimulable phosphor plate can be used repeatedly. becomes possible.

When this erasing means is provided, if the erasing control procedure for recording and reading image information is not performed appropriately, problems arise such as deterioration of image quality and delay in processing time. This will be explained in detail below.

First, image reading is performed by scanning a light beam from an excitation light source (including an optical system) such as a laser while irradiating the photostimulable phosphor plate with the scanning position changed in a direction perpendicular to this scanning direction. The light introduced from the condenser of optical fibers arranged corresponding to the light beam scanning surface of the phosphor plate is converted into an electrical signal by a photodetector such as a photomultiplier tube, and the excitation light source, condenser,
The excitation/reading unit, which includes a photodetector and the like, is controlled by a mechanical system to perform sub-scanning, which is called movement control, in a direction perpendicular to the main-scanning direction of light beam scanning.

Therefore, image reading is completed by moving the excitation/reading unit from one end of the stimulable phosphor plate to the last end, and returning the unit to the reading start position upon completion of image reading. Thereafter, in the control procedure in which an erasing lamp is turned on for a certain period of time to erase the afterimage on the stimulable phosphor plate, the processing time required for one recording, reading, and erasing becomes longer.

In addition, if an erasing lamp is integrally provided in the excitation/reading unit and the scanned portions are sequentially erased while reading the image, reading and erasing can be performed in parallel, reducing processing time. can. However, in this case, there is a problem in that the light from the erasing lamp enters the condenser or illuminates the scanning line being read, causing large noise in the read signal and deteriorating the quality of the read image. Furthermore, since reading and erasing are performed in parallel, either reading or erasing is subject to time constraints, making proper reading or erasing difficult. For example, in order to erase within the sub-scanning time of relatively fast reading, it is necessary to apply high-intensity erasing light to the stimulable phosphor plate, which requires a large and heavy erasing light source and its drive mechanism. This also increases the noise level to the read signal.

In addition, regardless of the erasing method described above, if there is a long interval between the end of erasing and the next imaging, the stimulable phosphor plate will accumulate radiation energy from other radiation sources, and the next imaging will be delayed. There was a problem of fogging that caused noise in the image.

Object of the Invention An object of the present invention is to provide a reading device that eliminates the intrusion of noise during imaging and reading, reduces processing time, and makes the excitation/reading unit and its moving mechanism smaller and lighter. It is in.

1. Structure of the Invention 1. The present invention includes a stimulable phosphor panel fixedly arranged to record a radiographic image, an excitation reading section for reading the radiographic image on a movable substrate-L that reciprocates, and an excitation reading unit for erasing the radiographic image. In the radiographic image recording and reading apparatus, the radiation image recording and reading apparatus further includes a second erasing means that is fixedly arranged on the main body of the reading apparatus, in addition to the erasing section on the movable substrate. It is.

One Embodiment - FIG. 1 is a configuration diagram of an apparatus showing one embodiment of the present invention, which is applied to chest X-ray photography. The radiation image information reading device 1 detects the radiation of the subject M by receiving radiation (indicated by an arrow) from an X-ray generation source (not shown) that has passed through the subject M into the stimulable phosphor plate 2. Record the image as a latent image. The excitation/reading unit 3 is provided in the reading device 1 on the back side of the stimulable phosphor plate 2 so as to be movable in the vertical direction by a lifting mechanism (not shown).

The excitation/reading unit 3 deflects a light beam from a light beam generator (not shown) such as a laser light source into a fan shape with a deflector 4 such as a rotating polygon mirror and extracts it as a scanning beam, and this scanning beam is used as a scanning beam for focus adjustment. It passes through a condensing lens 5 such as an f-theta lens, the optical path is further adjusted by a reflecting mirror 6.7.8, and then passes through a semi-transparent mirror 9 to excite the stimulable phosphor plate 2. A scanning beam is formed that forms a scanning line in the vertical direction. The light beam partially separated by the semi-transparent mirror 9 is taken into the light receiving element 11 through a focusing lens 1O, etc., and subjected to read signal processing in synchronization with the scanning beam.

The light condenser 12 has optical fiber condensing ends arranged parallel to the irradiation position of the scanning beam where the stimulable phosphor plate 2 is excited, and the stimulable phosphor plate 2 is excited by the scanning beam. Receives stimulated luminescence from 2. The light introduced from the condenser 12 is incident on the photocathode of the photodetector 13 through a filter or the like having a pass band in the stimulated emission wavelength region, and is transmitted to the photodetector as a current signal proportional to the weight of the incident light. 13 to III. This current signal is processed as a digital signal by an image information processing device (not shown) whose control center is a computer or the like.

The excitation light reading unit 3 and its A lowering mechanism having such a configuration scan the excitation light onto the stimulable phosphor plate 2 with a scanning beam (
While scanning in the downward direction (main scanning) perpendicular to the scanning direction (main scanning),
The scanning position is moved in the Y direction (in the figure), and the stimulated luminescence from the photostimulable phosphor plate 2 at each scanning point is detected between the light collector 12° and the photodetector 1.
3 and read as an electrical signal, and by processing this read signal, X-ray image information is obtained.

Here, the first erasing lamp 14 for erasing the afterimage of the stimulable phosphor plate 2 after reading is activated by the excitation/reading unit 3.
It is installed integrally with the

The erasing lamp 14 is a tungsten lamp, a nitrogen lamp, a fluorescent lamp, or the like, and has a light emitting surface slightly above the condensing end of the condensing body 12 on the back side of the stimulable phosphor plate 2 and arranged almost parallel to it. .

Further, a reflective hood 15 is provided so that the light from the erasing lamp 14 is efficiently concentrated on the surface of the stimulable phosphor plate 2, and the light from the erasing lamp 14 and the light reflected from the stimulable phosphor plate 2 are detected. In order to prevent the main surface of the light collector 13 from deteriorating, the light collector 12 and the photodetector 13 are provided with a light shielding cover 18 and a light shielding lid (not shown) that shields the light collecting end of the light collector 12 from light. .

Further, as second erasing lamps, a plurality of erasing lamps 171, 172, .
are provided substantially parallel to and opposite to the stimulable phosphor plate 2.

The erasing lamps 17+ to 17n are similar to the erasing lamp 14, and are arranged at intervals such that they can illuminate almost the entire back surface of the stimulable phosphor plate 2. Further, the erasing lamps 171 to 17n are provided with reflective hoods 18 and 18 on the back side, respectively.
n is provided to increase the efficiency of irradiation to the stimulable phosphor plate 2 side.

In addition, erase lamp 14.1? + - 17n, when using a lamp that emits radiation in response to radiation, such as a fluorescent lamp, a light shielding means is provided to cover the area other than the erasing part with a shutter, so that the radiation of the erasing lamp during photographing can be prevented from being emitted by the stimulable phosphor plate. 2 is prevented from being irradiated. In this case, when the light shielding means is made of lead glass, the movable stage thereof is unnecessary.

Among these erase lamps 14, 171 to 17n, the erase lamp I4 performs a reading operation while the excitation/reading unit 3 starts its reading operation and descends from the reading start position (highest position in the figure) to the reading end position (lowest position). The lights are turned off on the outward journey, and the lights are turned off on the return journey when the excitation-reading unit 3 moves from the reading end position to the reading start position.
The stimulable phosphor plate 2 is then erased.

Further, the erasing lamps 17+'' 17n are controlled to be turned on at all times, except for the period from photographing to reading, to perform an operation of erasing the stimulable phosphor plate 2.

FIG. 2 is a time chart showing one cycle control of photographing, reading, and erasing. At the time of photographing, the excitation/reading unit 3 is stopped at the reading start position, which is the highest position. When an X-ray imaging operation is performed, the operation control of the moving mechanism is started from when the imaging signal is received (time 1+),
When the excitation-reading unit 3 starts to descend and its movement speed becomes stable (time tz), the excitation light source, deflector, light-shielding means such as the photodetector 13° are turned on for the time TR necessary for reading, Causes a read operation to occur. By turning on each part only when necessary for reading, its lifespan is extended.

When this reading control is completed (time t3), the erasing lamps 17+ to 17n are controlled to light up, and erasing of the stimulable phosphor plate 2 is started. Furthermore, when the reading control ends, the excitation/reading unit 3 descends to the lowest position and is controlled to stop, and when the unit 3 is controlled to move to the reading start position (highest position) for the next reading (time t4) The erasing lamp 14 is controlled to turn on. Then, when the excitation/reading unit 3 is raised by 1 to the reading start position (time t5), the erasing lamp 14 is controlled to turn off. On the other hand, when shooting continuously, the erase lamp 17. ~
1? n continues to be lit until the next time of photographing, that is, until a photographing signal is given.

Therefore, reading and erasing are completely separated in time, and the light from the erasing lamps 14, 171 to 17n does not enter the read signal as noise. Since the reading time and erasing can be set independently, it is possible to obtain good reading and erasing operations by setting appropriate moving speeds for each reading and erasing.

In addition to this, the erasure lamp 14 is connected to the excitation and reading unit 3.
When the light is set to 51, the afterimage on the phosphor plate 2 to the cape I is erased, and the erase lamp 1? Since + to 17n are always turned on and erased except for the period between photographing and reading, erasing is performed by the cooperation of both erasing lamps, and the erasing lamp 14 is
The stimulable phosphor plate 2 can be sufficiently erased by being lightweight and relatively fast erasing.

Therefore, the excitation/reading unit 3 can be made smaller and lighter, and the moving mechanism can also be simplified. Furthermore, the time required for erasing can be shortened, and the cycle time of photographing, reading, and erasing can be shortened.

In addition, since the erasing lamps 171 to 17n are always on until immediately before photographing, when the interval between erasing and photographing is long, the stimulable phosphor plate 2 accumulates radiation energy from other radiation sources etc. during that time. It is also possible to prevent fogging that would cause noise in the next photographed image due to light leakage from outside the main body. In other words, in a device that does not have the erasing lamp 17+ "17n, erasing using the erasing lamp 14 must be performed immediately before photographing in order to prevent the above-mentioned fogging, and the problem with the erasing lamp 1?+ is that the erasing operation is required at the time of photographing, making it time-consuming to photograph. This problem can be solved by turning on the light up to 1?n all the time.

In addition, erase lamp +71 xl? Although the case where n is provided on the inner surface of the rear surface of the reading device 1 is shown, the stimulable phosphor plate 2 may be placed in a position where the stimulable phosphor plate 2 can be irradiated at the top and bottom or both sides of the device 1.

In addition, in the embodiment, the excitation/reading unit 3 is
Although the case where the excitation/reading unit 3 is moved horizontally or diagonally is shown, it is of course applicable to a reading device in which the excitation/reading unit 3 is moved horizontally or diagonally.

Effects of the Invention As described above, according to the present invention, the first erasing means is integrally provided in the excitation/reading unit, the second erasing means is fixedly disposed within the device, and the first erasing means is - Since the erasing operation is performed by moving the reading unit, and the second erasing means is made to perform the erasing operation at all times except during the period of photographing and reading operation,
This has the effect of eliminating the intrusion of noise into the read signal due to the erasing light, and reducing the size and weight of the excitation/reading unit and its moving mechanism while shortening the processing time.

[Brief explanation of drawings]

FIG. 1 is an apparatus configuration diagram showing an embodiment of the present invention, and FIG. 2 is a control time chart for photographing, reading, and erasing in the embodiment. l...reader, 2...stimulable phosphor plate, 3...
Excitation/reading unit, 4... Deflector, 5... Condenser lens, 12... Concentrator, 13... Photodetector, 14...
...first erasing lamp, 15...reflection hood, 16.
...Blackout cover, 171.1? n...Second erasing lamp, 181.18n...Reflection hood.

Claims (1)

[Scope of Claims] 1) A stimulable phosphor panel that records a radiation image that is fixedly arranged, an excitation reading section that reads the radiation image on a movable substrate that moves back and forth, and a third part that erases the radiation image. 1
A radiographic image recording/reading apparatus, characterized in that the radiation image recording/reading apparatus has a second erasing means fixedly arranged on the reading apparatus main body, in addition to the erasing section on the movable substrate. reading device. 2) The radiographic image information reading device according to claim 1, wherein the second erasing means has a control means that causes the erasing operation to be performed at all times except during imaging and reading.